The present disclosure generally relates to appliances, and more particularly to controlling hot water capacity and temperature in a water heater system.
Mixing valves in hot water heater systems are generally used to increase the hot water capacity of a hot water tank. By increasing the temperature of the hot water in the hot water tank, and then mixing the hot water flow from the hot water tank with cold water in a mixing valve, the realized capacity of the hot water tank is increased. Typical hot water systems that include a mixing valve generally seek to manage scalding risk and avoid temperature spikes that a user may experience without any interaction with a temperature control of the water heater.
The mixing valves for hot water heaters generally comprise a through-channel that is connected in series with a hot water supply line. A cold water inlet communicates with the through channel at an upstream side of a thermostat element. The thermostat element is located in the through-channel and functions to control the temperature of water passing from the mixing valve. A regulator valve element is located in a fluid passage between the cold water inlet and the through-channel. The regulator valve element is controlled by the thermostat element to regulate the quantity of cold water that is admitted into the through-channel to mix with the hot water.
The thermostat element that controls the regulator valve element of the mixing valve senses the temperature of the hot and cold water mix and controls the regulator valve element to provide a mix ratio which results in a pre-determined outflow temperature. The thermostat is typically adjustable to provide the pre-determined outflow temperature, also referred to herein as the hot water setpoint temperature. The mixing valve can detect the temperature of the water in the hot water supply line and introduce cold water into the hot water line when the hot water temperature is too high and reduce the temperature of the delivered water. However, these types of mixing valves can generally produce wide variations in the output temperature of the hot water that is delivered. It would be advantageous to be able to control an output of a mixing valve in a hot water system based on a user desired setpoint temperature for the hot water.
Water heaters are typically set to heat the water in the hot water tank to temperatures above approximately 120 degrees Fahrenheit. While a tank will typically have a limiting tank temperature of approximately 187 degrees Fahrenheit, it can be advantageous to be able to increase the temperature of the water in a hot water to temperatures of approximately 165 degrees Fahrenheit in order to reduce the probability of the occurrence of bacteria, such as legionella bacteria.
The typical hot water heater mixing valve is not capable of failure detection. If the mixing valve is faulty or the temperature is set too high, the temperature of the water delivered from the hot water heater can be too high. It would be advantageous to increase the hot water usability capacity of a hot water tank while minimizing the risks associated with the higher temperature hot water.
It can also be difficult to control the temperature of the hot water delivered from the hot water heater due to the mechanical nature of the mixing valve. With the typical mixing valve, a setpoint is chosen that approximates the desired hot water output temperature. It would be advantageous to be able to more precisely control the temperature of the hot water delivered from the hot water heater based on a desired user temperature setpoint.
Accordingly, it would be desirable to provide a hot water heater mixing valve that addresses at least some of the problems identified above.